charging voltage at idle (1 Viewer)

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I don't think you have a problem. The voltage is normally that low at idle, especially with it in gear and a load.
 
Ok. Those voltages were measured with it in gear with the AC on hi and the lights on at the scan gauge. Anything off idle was 13V+
 
Good info, it looks to be temp related. In the mornings when it is cool it shows 14v at idle when it is 95-100 it shows high 12's. Load on the alternator should be the same, does heat effect alt power output?

Temp does effect your readings, first your cold idle will be higher as will your voltage, next I assume your electric water pump or fan are designed to switch on when the engine warms up right? If yes you have answered your own question, if not then the slightly higher idle speed is covering your load. I do not think you have a problem if the driving voltages climb but, as sure as eggs are eggs you WILL have a problem if you are stuck in traffic for an excessive period of time with a voltage of under 13+ The point about cold AND heat killing batteries is spot on.

regards

Dave
 
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Well Dave I am a little ahead of the game as far as comparing high cold idle and regular idle. I really meant ambient temps, but both with the truck at the 650rpm idle set point. My fan and pump are for the intercooler not the engine so they run constantly but I have a switch to kill the fan at highway speeds.

I am convinced it isn't right. Was seeing 12.1 tonight, so it will be getting pulled. What's the vote on replacing brushes vs new alternator? These trucks are close to 20 years old. How much useful life in a replacing brushes really? Bearings, etc, do they usually go at a certain mileage?
 
If you can afford new then by all means go new. New brushes are a bandaid that can last 3 weeks or 3 years.
 
Lights, AC and stereo on.


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Everything off

1409278013299.jpg
 
SO it looks like the common alternator is the 80A, but that maybe there was a 90A and a 100A offered. Does anyone know anything about them and how to get them? The 90A looks like it was a "cold spec"
 
I just drove mine around, first start was 14.1V, once I turned the AC on and started driving, the voltage never really moved from 13.6V the whole time. This was idle and driving.
 
Sorry I assumed you meant you have a water pump/fan combo for the cooling system, either way the battery will not last at idle so get in there with the spanners. Noting your comment of 'wanting everything 100%' then personally I would not fit brushes and I would also not rebuild the standard unit, the stock unit was designed for just that 'stock'. There is of course a % extra to allow for ageing, towing a trailer perhaps a set of spot lights but that is about it. I would go for a new unit and as these are more or less bolt in units then why not upgrade, I went for the 150 amp unit (check the link in my sig) and I got mine from the states, a minor bracket mod as mine is a diesel and it plugged straight in but if you go for the 150 unit then replace the main charging wire from the alternator to battery.

regards

Dave
 
Well Dave I am a little ahead of the game as far as comparing high cold idle and regular idle. I really meant ambient temps, but both with the truck at the 650rpm idle set point. My fan and pump are for the intercooler not the engine so they run constantly but I have a switch to kill the fan at highway speeds.

I am convinced it isn't right. Was seeing 12.1 tonight, so it will be getting pulled. What's the vote on replacing brushes vs new alternator? These trucks are close to 20 years old. How much useful life in a replacing brushes really? Bearings, etc, do they usually go at a certain mileage?


FWIW, I agree with you, you are one step ahead of the game by noticing that the alternator is going out, if it is only putting out that voltage you are going to end up with a dead battery when running lots of accessories. I did the photoman 160 amp alt and it worked out great......
 
Yeah I am leaning that way. I have a couple emails out about the OEM 90A and 100A alternators. Hopefully someone knows something about them. Also the Toyota 80A alternator is $220 while the lexus 80A alternator is $365, both are discounted prices so trying to find out why the lexus is more.
 
Yeah ignore my statement. I don't know why I was thinking you had some heavy load.
 
Have you done a battery load test? A cell going bad on a battery will drag down everything. The monkeys at Autozoo can do it for free. Just have to disconnect the negative or positive for them so that you isolate the battery.
 
Yeah I am leaning that way. I have a couple emails out about the OEM 90A and 100A alternators. Hopefully someone knows something about them. Also the Toyota 80A alternator is $220 while the lexus 80A alternator is $365, both are discounted prices so trying to find out why the lexus is more.
If these help at all.

http://www.expeditionportal.com/forum/archive/index.php/t-12836.html
https://forum.ih8mud.com/80-series-tech/206807-upgrading-stock-alternator-130-150-amp.html
 
Yeah I am leaning that way. I have a couple emails out about the OEM 90A and 100A alternators. Hopefully someone knows something about them. Also the Toyota 80A alternator is $220 while the lexus 80A alternator is $365, both are discounted prices so trying to find out why the lexus is more.

You cant get under the hood to see the pink panties for less than $365. Report back but I'm sure they are the same. I rebuilt my alternator with new bearings and brushes (bearing was going bad). Year later the regulator was bad. Talked with Beno and just replaced the entire alternator. All good now.



Fat fingered from my iohone
 
Whoa whoa whoa!!

Don't we have to hash this out for like 50 pages first???
 
Only if he was overheating lol
 

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